I perform repairs/maintenance on the home for the life of the former homeowner.

Can anyone recommend a third party phone/answering service that can field and respond to maintenance requests from tenants?

Higher maintenance costs for rental houses. 

.#6 Lower Maintenance Costs:In comparison to small multifamily properties, single-family homes with ADUs often have lower maintenance and repair costs.

Then you have to manage the tenant and deal with maintenance and repairs.

Additionally, if you are looking to hold long term, having new construction is going to keep your repairs, maintenance and capex lower for quite a while, typically.  

I keep plenty of extra cash reserves to pay for repairs and maintenance.

I have no interest in trying to take advantage of them, I just don't want the aggravation of maintenance jobs.

If you have a worn out property with a lot of deferred maintenance in a lower end area that does not typically have the best tenants, then it may be worth it, because you will have more calls, more tenant issues, harder time leasing, more turnover work, etc.

Your concerns will likely be less with the tenants and more about learning things the previous landlord didn’t handle (deferred maintenance, whether the tenants pay on time consistently, etc)all the best!